Robot arm mechanism

Abstract

A purpose is to prevent a first connection piece string from colliding against a second connection piece string in a robot arm mechanism including a linear extension and retraction joint. In the robot arm mechanism having the linear extension and retraction joint, the linear extension and retraction joint includes an arm section, and an ejection section for supporting the arm section, the arm section includes a first connection piece string 21 made by a plurality of first connection pieces, and a second connection piece string made by a plurality of second connection pieces, the second connection piece string is sent out forward from the ejection section together with the first connection piece string in a state where the second connection piece string is joined to the first connection piece string, and a flexible guide rail for separating the first connection piece string from the second connection piece string and guiding the second connection piece string to the ejection section is interposed between the first connection piece string and the second connection piece string behind the ejection section.

What is claimed is: 
     
       1. A robot arm mechanism comprising a linear extension and retraction joint, wherein the linear extension and retraction joint includes an arm section, and an ejection section for supporting the arm section, the arm section includes a first connection piece string and a second connection piece string, the first connection piece string includes a plurality of first connection pieces, and the second connection piece string includes a plurality of second connection pieces, the second connection piece string is sent out forward from the ejection section together with the first connection piece string in a state where the second connection piece string is joined to the first connection piece string and constitutes a columnar body with the first connection piece string, and the robot arm mechanism further comprises a guide rail interposed between the first connection piece string and the second connection piece string, wherein the guide rail comprises a plurality of rail pieces connected in a series, and wherein the guide rail is connected to a rear portion of the ejection section. 
     
     
       2. The robot arm mechanism according to  claim 1 , wherein a bending angle of the guide rail toward the first connection piece string side is limited. 
     
     
       3. The robot arm mechanism according to  claim 1 , wherein each of the rail pieces is provided with a wheel. 
     
     
       4. The robot arm mechanism according to  claim 3 , wherein a surface of each wheel is covered with an elastic body. 
     
     
       5. The robot arm mechanism according to  claim 3 , wherein the rail pieces are connected at intervals which are shorter than a length of the second connection pieces.